Establishing a trust relationship between realms creates a shortcut for authentication.
This function is optional because by default the Kerberos protocol will search the realm hierarchy looking for trust. This function is useful if you have realms in different domains and want to make this process faster. To set up realm trust, each Kerberos server for each realm must share a key. Before you can create a trust relationship in network authentication service, you must set up the Kerberos servers to trust one another. To create a trust relationship among realms, complete the following steps: